Surgical instruments and procedures for stabilizing the beating heart during coronary artery bypass graft surgery

ABSTRACT

The invention is methods and devices which a surgeon may use to stabilize the beating heart during a surgical procedure on the heart. Pursuant to the invention, a stabilizing device is introduced through an opening in the chest and brought into contact with the beating heart. By contacting the heart with the device and by exerting a stabilizing force on the device, the motion of the heart caused by the contraction of the heart muscles is effectively eliminated such that the heart is stabilized and the site of the surgery moves only minimally if at all. Typically, in separate steps, the surgeon contacts the heart with the stabilizing device, assesses the degree of movement of the anastomosis site, and exerts a force on the stabilizing device such that the contraction of the beating heart causes only minimal excess motion at the surgery site. By fixing the position of the stabilizing device in a configuration where the motion of the beating heart is effectively eliminated, the surgeon is able to stabilize the beating heart for the duration of the procedure. The stabilizing device may be attached to a rigid support or may be attached to a semi-rigid support which is rendered motionless mechanically, chemically, or by human intervention. In certain preferred embodiments, the stabilizing device is affixed to a semi-rigid support which is caused to become rigid, by any of a variety of techniques, such that the position of the stabilizing device becomes fixed by the support, and the heart remains substantially motionless for the duration of the procedure.

The present application is a continuation of U.S. application Ser. No.09/550,447 filed Apr. 17, 2000, now U.S. Pat. No. 6,315,717 and titled“Surgical Instruments For Stabilizing The Beating Heart During CoronaryArtery Bypass Graft Surgery”, which is a divisional of U.S. applicationSer. No. 09/099,855, filed Jun. 18, 1998, now U.S. Pat. No. 6,050,266,which is a divisional of U.S. application Ser. No. 08/603,758 filed Feb.20, 1996, now U.S. Pat. No. 5,894,843, all of which are herebyincorporated by reference thereto, in their entireties.

Diseases of the cardiovascular system affect millions of people eachyear and are a leading cause of death in the United States andthroughout the world. The costs to society from such diseases isenormous both in terms of the lives lost and in terms of the cost oftreating patients through surgery. A particularly prevalent form ofcardiovascular disease is a reduction in the blood supply leading to theheart caused by atherosclerosis or other condition that creates arestriction in blood flow at a critical point in the cardiovascularsystem that supplies blood to the heart. In many cases, such a blockageor restriction in the blood flow leading to the heart can be treated bya surgical procedure known as a Coronary Artery Bypass Graft (CABG)procedure, which is more commonly known as a “heart bypass” operation.In the CABG procedure, the surgeon removes a portion of a vein fromanother part of the body to use as a graft and installs the graft atpoints which bypass the obstruction to restore normal blood flow to theheart.

Although the CABG procedure has become relatively common, the procedureitself is lengthy and traumatic and can damage the heart andcardiovascular system, the central nervous system, and the blood supplyitself. In a conventional CABG procedure, the surgeon must make a longincision down the center of the chest, cut through the entire length ofthe sternum, perform several other procedures necessary to attach thepatient to a heart-lung bypass machine, cut off the blood flow to theheart, and then stop the heart from beating in order to install thegraft. The lengthy surgical procedures are necessary, in part, toconnect the patient to a cardiopulmonary bypass machine to continue thecirculation of oxygenated blood to the rest of the body while the bypassgraft is sewn into place.

Although several efforts have been made to make the CABG procedure lessinvasive and less traumatic, most techniques still require cardiacbypass and cardioplegia (stoppage of the heart). The safety and efficacyof CABG procedure could be improved if the surgeon could avoid the needto stop the heart from beating during the procedure, thereby eliminatingcardiopulmonary bypass and the lengthy and traumatic surgical proceduresnecessary to connect the patient to a cardiopulmonary bypass machine tosustain the patient's life during the procedure. In recent years, asmall number of surgeons have begun performing CABG procedures usingsurgical techniques especially developed so that the CABG procedurecould be performed while the heart is still beating. In such procedures,there is no need for any form of cardiopulmonary bypass, no need toperform the extensive surgical procedures necessary to connect thepatient to a cardiopulmonary bypass machine, and no need to stop theheart. As a result, the surgery is much less invasive and the entireprocedure can typically be achieved through one or two comparativelysmall incisions in the chest.

Despite the advantages, the beating-heart CABG procedure is not widelypracticed, in part, because of the difficulty in performing thenecessary surgical procedures using conventional instruments. If specialdesigned instruments were available so that the CABG procedure could beperformed on the beating heart, the beating-heart CABG procedure wouldbe more widely practiced and the treatment of cardiovascular disease ina significant patient population would be improved.

As noted above, the CABG procedure requires that a connection for theflow of blood be established between two points to “bypass” a diseasedarea and to restore blood flow to the heart. This procedure is known asan “anastomosis.” Typically, one end of the by-pass graft is sewn to asource artery with an unobstructed blood flow, such as the left internalmammary artery (LIMA), while the other end of the graft is sewn to atarget coronary artery, such as the left anterior descending (LAD)artery, that provides blood flow to the main muscles of the heart.Because the beating-heart CABG procedure is performed while the heartmuscle is continuing to contract and pump blood, the anastomosis isdifficult to perform because the heart continues to move and to attemptto pump blood while the surgeon is sewing the graft in place. Thesurgical procedure necessary to install the graft in the beating-heartCABG procedure requires placing a series of sutures through severalextremely small vessels that continue to move during the procedure.Moreover, the sutures must be carefully placed so that the graft isfirmly attached and does not leak when blood flow through the graft isestablished. It is also important that the procedure be performedrapidly because the blood flow through the target coronary artery isinterrupted or reduced during the procedure to allow the graft to beinstalled without excessive blood loss. Also, the working space andvisual access are limited because the surgeon may be working through asmall incision in the chest or may be viewing the procedure on a videomonitor if the site of the surgery is viewed via a surgical scope.

A current practice is for the surgeon to place sutures through the hearttissue and, by exerting opposing tension on the sutures, stretch thetissue surrounding the anastomosis to partially reduce the motion of theheart while the graft is installed. This approach is far from ideal.Alternatively, a suction device may be attached to the surface of theheart to fix the motion of the outer layer of surface tissue. In suchcases, a suction device typically has several ports incorporated into aninstrument may be attached to the heart to apply a negative pressure tothe surface tissue. The negative pressure essentially attaches thesurface tissue to the apparatus thereby fixing the position of a portionof the surface of the heart. Such devices are described in co-pendingapplication Ser. No. 08/603,328 and U.S. Pat. No. 5,727,569.

While the negative pressure approach may be effective in fixing aportion of the surface tissue of the heart, the negative pressureapplied to cardiac tissue can result in temporary hematomas at the sitewhere the suction ports attach to the tissue. Also, the exterior cardiactissue is fixed in a configuration defined by the shape of theinstrument and the orientation of the suction ports. While the heartcontinues to beat, the heart muscles are contracting to pump blood,which results in the muscles exerting a force directed away from theexterior tissue fixed by suction.

The beating-heart CABG procedure could be greatly improved if the heartcould be stabilized during the procedure such that the motion of theheart, particularly at the site of the anastomosis, is minimized eventhough the heart continues to beat. If effective means for stabilizingthe beating heart were available, the beating heart CABG procedure couldbe performed more easily, more rapidly, more safely, and with lesstrauma to the patient.

SUMMARY OF INVENTION

The advantages provided to a surgeon by the instruments and techniquesof the invention allow the beating heart CABG procedure to be performedmore rapidly with less trauma to the patient, and without CPB orcardioplegia. This invention provides an alternative approach to thesuction apparatus by providing devices and methods for stabilizing themotion of the heart using mechanical instruments specially designed toapply a stabilizing force to the heart to minimize the motion of thebeating heart during a surgical procedure. The invention enables asurgeon to readily and rapidly perform a beating-heart CABG procedurewithout the need for cardioplegia or cardiopulmonary bypass. Inparticular, the methods and devices described here enable the surgeon tostabilize the heart such that an anastomosis can be more readilyaccomplished by enabling the surgeon to attach the graft to a targetcoronary artery whose motion is minimized for the duration of thesurgical procedure.

Pursuant to the invention, a stabilizing device is introduced through asuitable opening in the chest to provide access to the beating heart. Bycontacting the heart with the stabilizing means of this invention and byexerting a stabilizing force on the heart, the motion of the heartcaused by the contraction of the heart muscles is effectively eliminatedsuch that movement of the target artery at the site of the surgery isminimized. The remainder of the heart may be allowed to contractnormally or may have additional devices in place to support the heart orto restrain its motion. An important advantage of this invention isderived from the discovery that an effective procedure can be followedusing the devices of the inventors to provide an advantageous techniquefor stabilizing the beating heart. The procedure requires exerting astabilizing force on the beating heart using devices constructed asdescribed herein. Typically, in separate steps, the surgeon contacts theheart with the stabilizing means, assesses the degree of movement at thesite of the surgery and positions the stabilizing means proximate to thetarget coronary artery. With the stabilizing means in place, the surgeonapplies a stabilizing force to the stabilizing means by applying a forcesuch that the portion of the instrument in contact with the surface ofthe heart displaces the surface of the heart a sufficient distance thatthe contraction of the heart does not cause either vertical orhorizontal motion at the surgery site. The stabilizing force is appliedby the stabilizing means of the invention and comprised of exerting amechanical force onto the beating heart at the location of the targetcoronary artery. Thus, an important aspect of this invention is thediscovery that the beating heart may be effectively stabilized for thepurpose of a surgical procedure by using a specially designed instrumentas described herein to exert a mechanical stabilizing force on theexterior of the heart proximate to the site of the surgery.

By fixing the position of the stabilizing means in a configuration wherethe motion of the beating heart is effectively eliminated, the surgeonmaintains the stabilizing force on the beating heart for the duration ofthe procedure. To fix the position of the stabilizing means, the meansmay be attached to a retractor used to separate the ribs or to anotherfixed support. Alternatively, the stabilizing means may be attached to asemi-rigid conformable arm which is rendered rigid by mechanically,chemically, or by human intervention. In certain preferred embodiments,the stabilizing means has an adjustable shaft means which may beoriented in several directions and has a fixture adapted to be attachedto a retractor. In a preferred technique of the invention, the surgeonfirst performs a thoracotomy, retracts the ribs using a retractor whichis locked in an open position providing access to the beating heart. Thesurgeon then contacts the surface of the heart with the stabilizingmeans at a point proximate to the target coronary artery, and exerts astabilizing force on the stabilizing means until the site of the surgeryis substantially motionless. At this point, the adjustable shaft meansis positioned and fixed in place by attachment to the retractor therebyrendering the target coronary artery substantially motionless for theduration of the procedure.

DESCRIPTION OF THE FIGURES

FIG. 1 is a means for stabilizing the beating heart having a pair ofsubstantially planar contact members which engage the heart on eitherside of a target coronary artery to which a bypass graft is sewn. FIG. 1also shows the contact members attached to a shaft means which may beadjustable in several directions and which may be attached to aretractor or other fixed support structure. FIG. 1A is detail of theshaft means and the structure of the adjustable positioning mechanisms.FIG. 1B is a contact member having a friction means which is preferablyaffixed to the bottom surface of the contact member.

FIG. 2 is an alternate embodiment of a stabilizing means having a singleshaft means associated with each contact member and where the shaftmeans are interconnected and can be moved independently about a pivotsuch that the contact members spread the surface tissue of the heartproximate to the target coronary artery to increase exposure of thetarget artery at the site of the anastomosis.

FIG. 3 is a means for stabilizing the beating heart having a pair ofcontact members which are additionally comprised of a spring-tensionedframe having an extension that engages and spreads the tissue at thesite of the surgery to better expose the coronary artery.

FIG. 4 is an inflatable means for stabilizing the beating heart having asheath member with several pliable support attachments associatedtherewith which may include or be comprised of inflatable members whichare positioned at one or several locations surrounding the heart and mayhave a lumen disposed within the sheath member for the introduction ofair or a biocompatible fluid.

FIG. 5 is a means for stabilizing the beating heart comprising a systemwhich incorporates the retractor which spreads the ribs to providesurgical access to the heart. The stabilizing means is comprised of apair of stabilizing plates which may be used together with a leverdevice to improve exposure of the target coronary artery.

FIG. 6 is a flexible, lockable arm which allows positioning in everydirection to place and orient the contact members until the requisitedegree of stabilization is achieved at which point the arm having astabilizing means is fixed in position. The flexible, lockable arm maybe attached to a retractor and is caused to become rigid when the entirestabilizing means is properly positioned.

FIG. 7 is a substantially planar stabilizing platform which contacts theheart at a site proximate to and surrounding the coronary vessel. Theplatform may also have associated therewith at least one occluder whichrestricts or eliminates blood flow through an artery and an associateddevice for spreading the tissue proximate to the anastomosis.

FIG. 8 is a stabilizing contact member having means associated therewithfor attaching a snap fixture or other method of attachment to thestabilizing member such that the cardiac tissue is attached to thecontact member.

FIG. 9A is a view of the interior of the chest cavity during a CABGprocedure on the beating heart with the stabilizing means operablyassociated with a retractor and being used in conjunction with othersurgical apparatus to facilitate completing the anastomosis. FIGS. 9Band 9C show the stabilizing means of the invention having beenintroduced through a thoracotomy to contact the beating heart to engagethe heart tissue on either side of a target coronary artery to which ananastomosis is sewn.

FIG. 10 is an embodiment of the stabilizing means of the inventionhaving a pair of plates operably associated with a rib retractor and asphere disposed between the plates to facilitate orientation of theshaft means.

FIG. 11 is an embodiment of the stabilizing means of the inventionhaving stabilizer bars suspended from the bottom side of a rib retractorwherein the stabilizer bars engage a ratchet means.

FIG. 12 is an embodiment of the invention having malleable supportsattached at the ends on the contact members and attached to the ribretractor.

DETAILED DESCRIPTION OF THE INVENTION

This invention is surgical instruments for stabilizing the beating heartand methods for their use. The means for stabilizing the beating heartare comprised of several alternative structures which engage the surfaceof the heart to stabilize the beating heart during coronary surgery. Theinstruments provide the capability to exert and maintain a stabilizingforce on the heart by contacting the heart with the stabilizing meansand by fixing the position of the stabilizing means throughout theduration of a surgical procedure.

The instruments and methods of the invention are preferably used forstabilization of the beating heart during a minimally invasive coronaryartery bypass graft (CABG) operation which has been specially developedto facilitate placement of a bypass graft without cardioplegia orcardiopulmonary bypass. Although the means for stabilizing the beatingheart can be applied in different surgical contexts, the devicesdescribed herein are most advantageously employed in a CABG procedurewherein only one or two incisions are placed in the chest. The structureof the stabilizing means may be described by several structuralembodiments which stabilize the beating heart while the minimallyinvasive surgical procedure is performed. The stabilizer means may alsoadvantageously function in a multiple component system containing aretractor, an occluder, a surgical blower or suction device, anapparatus for holding the source artery, such as a LIMA holder, or otherlike devices to enable a surgeon to more efficiently complete theanastomosis. While the devices disclosed herein each use mechanicalmeans to stabilize the beating heart, certain embodiments are designedto operate on the entire heart while others have more localized effectand may be applied to the area immediately proximate to a structure suchas the target artery of the anastomosis. In each instance, the beatingheart is effectively stabilized at the area where a surgical procedureis to be performed. Surgical access to the beating heart may be achievedby several conventional cardiac surgical procedures which have beendeveloped for traditional bypass surgery. The surgeon may obtain theadvantages provided by the invention in any procedure where the bypassis achieved on the beating heart. When access to the beating heart isachieved by a sternotomy, the length of the sternum is separated toexpose the surface of the heart. Preferably, the surgeon takesadditional measures to restrict the movement at the entire heart withinthe chest cavity. For example, an inflatable cushion with straps orlaces may be inserted beneath or surrounding the heart. Additionally,when the pericardium is available, the pericardium may be incised andused to position the beating heart. When the pericardium is available,the surgeon can use the pericardium to raise and rotate the beatingheart within the chest cavity and maintain the position by suturing thepericardium to the periphery of the incision.

In the preferred embodiment, minimally invasive access to the beatingheart is achieved by a thoracotomy, which is usually created in the leftside of the chest by a vertical incision between the ribs, insertion ofa retractor between the ribs, followed by spreading of the ribs andsecuring the retractor in an open position to provide access to thesource artery and the target coronary artery. The use of the pericardiumto position the beating heart as described above is particularlyadvantageous when the less invasive thoracotomy is used to provideaccess to the heart. An incision is created in the pericardium which isthen sutured to the periphery of the thoracotomy. In this configuration,the pericardium acts as a restraining sac to keep the beating heart in adesired orientation to achieve the anastomosis. The means forstabilizing the beating heart is introduced through the opening createdby the thoracotomy and is brought into contact with the heart. Thesurgeon applies a stabilizing force to the heart via the stabilizingmeans which may then be fixed in place by attachment to a fixed support.When the rib retractor or platform is fixed in an open position toexpose the heart, the retractor platform may also provide anadvantageous stable support structure to which the stabilizing means maybe affixed. When the position of the stabilizing means is fixed byattachment to a stable support or to the retractor platform, thestabilizing force is maintained for the duration of the procedure.

Although the particular source and target artery of the anastomosis aredetermined clinically, common minimally invasive bypass procedure on thebeating heart comprises an anastomosis which forms a connection betweenthe left internal mammary artery (LIMA) as the source artery and theleft anterior descending artery (LAD) as the target artery. The LIMA toLAD anastomosis is used as an example herein but it is readilyappreciated that the techniques and instruments described herein may beapplied to other procedures depending on the clinical diagnosis. Tocomplete the anastomosis, the surgeon must dissect a portion of the LIMAby separating it from the internal chest cavity. Once dissection of theLIMA is achieved, the surgeon may attach the dissected LIMA to thetarget cardiac artery, in this example, the LAD. In this example, thestabilizing means of this invention would be used to stabilize thebeating heart during at least the portion of the procedure during whichthe surgeon completes the anastomosis to the LAD.

The structure of the portion of the stabilizing means which contacts theheart includes an inflatable member, a platform which may besubstantially planar or which may be contoured to fit conformingly onthe surface of the heart, one or more contact members which exert astabilizing force on the heart proximate to the site of the anastomosis,a pair of contact members which may be plates or rectangular memberswhich are placed on either side of the target coronary artery at thesite of the anastomosis and which may have a friction or tissuespreading means associated therewith. The stabilizing means may alsoinclude a shaft means having several alternative embodiments tofacilitate adjusting the position and orientation of the instrument. Forexample, the shaft means may have an, adjustable length and the axis ofthe shaft means may have at least one ball joint disposed within itslength such that the orientation of the shaft means relative to anotherstructure such as the contact members on the retractor may becontinuously varied. As is apparent from the description of the severalembodiments, each of the individual embodiments described andillustrated herein has discrete components and features which may bereadily separated from or combined with the features of any of the otherseveral embodiments without departing from the scope of the invention.

Referring to FIG. 1, a stabilizing means is comprised of one or more,and preferably two, contact members 1, which are attached to a rigid, orsemi-rigid connecting shaft 2 which is in turn connected to shaft means3. The contact members 1 may be substantially planar or may be slightlycurved to conform to the shape of the heart. The contact members 1 mayhave any of several alternate shapes including cylindrical membersformed into a U-shape or may comprise a pair of substantially parallelmembers spaced apart in a parallel configuration such that a targetartery can be positioned between the contact members. The shape of thecontact members may be varied depending on the clinical assessment bythe surgeon, the design of the other features of the stabilizing means,or the design of other instruments used to complete the anastomosis. Insome embodiments, as described herein, the contact members 1 may haveapertures, openings or attachments to facilitate connection with suturesor other devices to achieve the requisite stabilization. In a preferredembodiment, a pair of substantially planar rectangular contact members 1are attached at one end to a continuous connecting shaft 2 and areoriented in a substantially parallel fashion such that a target cardiacartery is positioned therebetween and passes along the length of thecontact members 1 when the stabilizing means engages the heart. SeeFIGS. 9A-C. While the contact members 1 may each be connected to theconnecting shaft 2 at one end, with the connecting shaft 2 operablyattached to shaft means 3, the configuration of the connecting shaft 2relative to the contact members 1 may be altered depending on theconfiguration of the contact members 1 and the clinical aspects of theprocedure. For example, the connecting shaft may be continuous toconnect with the contact members 1 without touching the artery or mayinclude an additional member which may be operated to contact the targetartery positioned between the contact members 1, see FIG. 8, to occludethe passage of blood through the target artery. The contact members 1,connecting shaft 2 and shaft means 3 may be composed of any non-toxicmaterial such as a biocompatible plastic or stainless steel, havingsufficient tensile strength to withstand a stabilizing force exerted onthe heart via manipulation of the shaft means 3 to cause the contactmembers 1 to exert a stabilizing force on the beating heart.

The shaft means 3 may be a simple rigid post or may be comprised of amulti-component system designed to be adjustable in length andorientation at least one point along its length. Thus, the length of theshaft means 3 and the orientation of the contact members 1 at the distal(lower) end of the shaft means 3 can be altered by the surgeon.Preferably, the length and orientation at the shaft means 3 relative tothe contact members 1 can be adjusted by controls located at theproximate (upper) end of shaft means 3. This design provides theadvantage that the surgeon can introduce the stabilizing means to thebeating heart by placing the contact members 1 on the surface of theheart, exerting a stabilizing force, and then locking the contactmembers 1 in place relative to the shaft means 3. Furthermore, thesurgeon may then lock the shaft means 3 into a fixed position byattachment to a stable support such as the retractor, therebymaintaining the stabilizing force for the duration of the procedure. Inone embodiment, the shaft means 3 has a housing 11 whose overall lengthis adjustable by a telescoping release 4 operated by an annularthumbscrew 10 which tightens about the housing 11. The position andorientation of the contact members 1 relative to the shaft means 3 isadjustable by virtue of a locking ball joint 5 which is interposedbetween the connecting shaft 2 and which is located at the distal end ofshaft means 3. The locking ball joint 5 allows the position of the shaftmeans 3 to be positioned with three degrees of freedom relative to thecontact members 1.

Referring again to FIG. 1, a locking ball joint 5 is provided byincluding a block 6 within the shaft means 3 which conformingly contactsthe ball joint 5 and fixes the position of the ball joint 5. Block 6 iscompressed against ball joint 5 when a threaded push block 7 isconnected to a long allen 9 is actuated by means such as a thumbscrew 8at the upper end of the shaft means 3. In operation, a rotation of thetop thumbscrew 8 loosens the lower ball joint 5 to allow continuouspositioning of the shaft means 3 relative to the contact members 1, anda counterrotation locks the ball joint 5 into place, fixing the positionof the contact members 1 relative to shaft means 3.

The upper end of shaft means 3 may also have associated therewith anupper ball joint 13 such that the shaft means 3 can be oriented withthree degrees of freedom relative to a fixed support such as aretractor. The position and orientation of the shaft means 3 may thus befixed relative to the stable support by a locking latch 14 or otherconventional mechanism which prevents movement of the upper ball joint.Either the shaft means 3 or the retractor may contain the locking latch14 surrounding the upper ball joint 13 or any like fixture to firmlyattach the shaft means 3 to a stable support, e.g., an anchor portion 15extending from the retractor (not shown).

Referring to FIG. 1B, the contact members 1 preferably have frictionmeans 4 associated with their bottom surface 5 such that the contactmembers 1 more securely engage the beating heart when a stabilizingforce is exerted on the shaft means 3. The friction means 4 preferablycomprises a textured surface covering the bottom surface 5 of thecontact member 1, and may be comprised of several bio-compatiblesubstances such as a textured rubber, textured or ridged aluminum,stainless steel or the like.

As noted above, at the upper end of the shaft means 3, the shaft means 3may be attached to a fixed support, such as by anchor portion 15, whichmay be any surface or structure which does not move with the beatingheart. For example, the shaft means 3 may be attached to a fixture onthe retractor system used to spread the ribs for access to the heart ormay be attached to a fixed structure such as the surgical table orassociate aperture which is not connected to the patient. In a preferredembodiment, the shaft means 3 is directly attached to a component of theretractor system which is designed to receive the shaft means 3 and tomaintain the position and orientation of the shaft means 3 during theprocedure.

The shaft means 3 may also be attached, to or comprised of, aconformable arm which is used to position the stabilizing means againstthe heart and then to lock the stabilizing means in place once astabilizing force has been exerted. The conformable arm is flexible andlockable and may have several configurations including a plurality oflinks, segments, or universal joints in serial configuration and havinga cable fixture passed through the interior of the links which cause theentire conformable arm to become rigid by tightening the cable fixture.Also, the conformable arm may be comprised of a synthetic gel or polymercontained within a conformable cylindrical housing and which becomesrigid upon exposure to light or heat, such as the commercially availableDymax 183-M. Where the shaft means 3 is further comprised of theconformable arm, the conformable arm may be attached directly to theconnecting shaft 2 or the contact members 1.

Referring to FIG. 2, the stabilizer means may also be comprised of asingle shaft means 3 connected to each contact member 1. In a preferredembodiment, the shaft means 3 are interconnected at an intermediatepivot point 16 which permits the contact members 1 to be continuouslypositioned in parallel fashion relative to one another. The proximate(upper) portion of the individual shaft means 3 may have grips adaptedto be grasped by the hand or may have an anchor portion 15 forattachment to a retractor or other fixed support. As with the otherembodiments described herein, the length of the shaft means 3 may beadjustable by a conventional telescope configuration. In such aconfiguration, a first shaft 18 has a partially hollow segment 17adapted to receive the complimentary portion of the second shaft 19.Either first 18 or second 19 shafts may be connected to the contactmembers 1 and may each have a conventional locking mechanism (notshown). The shaft means may also have a tensioning spring mechanism 20having an axis 21 which is displaced between a portion of the shaftmeans 3 affixed to the contact members 1 and the remainder of the shaftmeans 3. In this configuration, the contact members 1 remain tensionedagainst the heart proximate to the anastomosis site when the proximalend of the shaft means 3 is affixed to a stable support. The shaft meansmay also comprise an interlocking mechanism 90 to fix the position of asingle shaft 18 relative to the other. This embodiment also preferablyhas a friction means 4 as described above attached to each contactmember 1. An additional advantage of this embodiment is derived from thecapability to move the contact members I apart from one another in aparallel configuration. Thus, the contact members 1 can first bepositioned to engage the surface of the heart tissue, followed by theapplication of a stabilizing force in combination with spreading of theproximate (upper) end of the shaft means 3. Application of a stabilizingforce causes the tissue on either side of the target artery to bestabilized. By coincidentally spreading the proximate portion of theshaft means 3, the tissue engaged by the contact members 1 is stretchedto provide stabilization and improved exposure of the target coronaryartery.

Referring to FIG. 3, the contact members 1 may be further comprised of aspring-tensioned frame 210 having a movable frame extension 22 which mayhave pins or an associated friction means 4 to engage the tissueproximate to the target artery. The movement of the frame extension 22is tensioned by a spring means 23 which draws the frame extension 22toward the contact member 1 after the frame extension 22 has beenmanually positioned to engage the tissue. The use of this embodiment ofthe invention is the same as is described for the other embodimentsherein, with the frame extension 22 providing improved exposure of thetarget artery. As with the other embodiments of the invention disclosedherein, the contact members 1 may be attached at one end by a connectingshaft 2 which is attached to a shaft means 3 as described above. Theconnecting shafts 2 may also be positioned relative to one another by aconventional threaded post 24 with a positioning thumbscrew 25.

Referring to FIG. 4, this embodiment of the stabilizing means iscomprised of an elongated sheath member 26 which wraps around the heartin a strap-like fashion to restrict the motion of the heart. Thisembodiment is particularly useful when access to the beating heart isprovided by a sternotomy. The sheath member 26 is positioned to surroundthe heart and manipulated so that each end of the sheath member 26extends out of the chest cavity through the sternotomy. If desired, atleast one end of each sheath member 26 is attached to the retractor tosecure the position of the sheath member 26. The sheath member 26 mayhave a plurality of support attachments 27 which engage the exterior ofthe heart to hold it in place. At the point where the supportattachments 27 contact the surface of the heart, the support attachments27 may have friction means 4 attached to the surface which is in directcontact with the heart. The support attachments 27 may have or becomprised of inflatable members 28 which cushion the heart against thesheath member 26, and absorb the motion of the heart while it isstabilized. Where the sheath member 26 has a plurality of inflatablemembers 28, the sheath member 26 is preferably further comprised of atleast one lumen 29 for introduction of air or a biocompatible fluid tothe inflatable members 28, which may be inflated separately orsimultaneously. In the former instance, a separate lumen 29 is providedfor each inflatable member 28. The insertion of the sheath member 26into the chest cavity should be performed while the inflatable members28 are deflated and is achieved manually or by a conventional guideand/or guidewire. Each of the support attachments 27 may be permanentlyattached to the sheath member 26 or may slide along the length of thesheath member 26. Alternatively, alone or in combination with at leastone other inflatable member 28, an inflatable member 28 may bepositioned immediately proximate to the target coronary artery toachieve a more localized stabilization. The inflatable member 28 ispositioned to lie next to, or may surround, the target coronary arteryand may have openings or apertures placed in the body of the memberthrough which surgical procedures are performed.

Referring to FIG. 5, the stabilizer means may comprise at least onestabilizer plate which is attached to a stable support and which may beused with a lever member for improving exposure at the target arterywhile the anastomosis is completed. In this embodiment, the means forstabilizing the beating heart comprises a left and right stabilizingplate 30, 31 which are oriented to exert a downward force on the tissueat either side of the target artery at the anastomosis site and whichmay be substantially planar or may be curved to conform to the surfaceof the heart. One or both of the stabilizing plates 30, 31 may have anedge 27 deflected downward along its length so that the edge 27depresses the tissue proximate to the artery to increase the exposure ofthe artery during the completion of anastomosis. Preferably, the edge 27of the stabilizing plates 30, 31 has a separate lever member 33 runningsubstantially parallel to the artery and on both sides thereof. The topportion of each lever member 33 contacts the underside of thestabilizing plates 30, 31. In this embodiment, the lever member 33 issubstantially cylindrical, traverses the stabilizing plate along itslength, and is oriented to be parallel to the edge 27 of the stabilizingplate 30, 31. The lever member 33 is fixed in place, and may be affixedto the heart by a suture. In such a configuration, each of thestabilizing plates 30, 31, which is in contact with the lever member 33along its length, contacts the heart such that the edge 27 depresses thetissue on both sides of the target coronary to restrict the movement ofthe beating heart. The stabilizing plates 30, 31 can be attached to oneanother or can move independently as desired.

Opposite the edge 32, at a point separate from the lever member 33, thestabilizing 30, 31 plate is connected to a shaft means 3 which holds thestabilizing plate 30, 31 in position and which may be manipulatedrelative to the lever member 33 to cause the edge 27 to engage theheart. The shaft means 3 is preferably affixed to each stabilizing plate30, 31 at a point opposite the edge 27 and removed from the point wherethe lever member 33 contacts the stabilizer plate 30, 31 at a locationto maximize leverage when the stabilizer plates 30, 31 are drawn upwardsat the point of attachment of the shaft means 3. The shaft means 3 maybe constructed as described elsewhere herein and should be of sufficientlength to facilitate manipulation of the shaft means 3 by the surgeon.As noted, the shaft means may also be attached to the retractor to fixmovement of the stabilizing plates 30, 31 during the procedure.

In a preferred embodiment, the length of the shaft means 3 is adjustablerelative to the retractor or other stable support. For example, theshaft means 3 may be telescopic as described above or may be comprisedof a hollow post 34 which receives a rigid shaft 35 which is in turnfixed to the retractor. The rigid shaft 35 may also be substantiallyhollow and may have a suture or other line 36 passed therethrough andwhich also passes through the length of the hollow post 34. In thisconfiguration, one end of the suture or line 36 is attached to thestabilizing plate 30, 31 and the other end extends through the hollowpost 34 or the rigid shaft 35 to a position where it may be manipulatedby the surgeon. The position of the stabilizing plate 30, 31 may therebybe remotely actuated. By drawing tension on the suture or line 36, thestabilizing plate 30, 31 pivots about the lever member 33 and the edge32 of the stabilizer plates 30, 31 depress the tissue on either side ofthe target artery.

Referring to FIG. 6, this embodiment of the invention is a means forstabilizing the beating heart wherein the shaft means is comprised of aflexible, lockable arm 37 having a plurality of interconnecting links 38which allow positioning of the flexible arm 37 in every direction untilthe desired configuration is achieved at which point the flexible arm 37may be locked into fixed configuration by tightening a cable fixture(not shown) attached to a cable 39 running axially through theinterconnecting links 38. Each interconnecting link is comprised of aball portion 38 a and a receiving portion 38 b such that the ballportion 38 fits conformingly within the receiving portion 38 b. Theproximate (uppermost) end of the flexible, lockable arm 37 can beattached to a stable support, or to the retractor. In a preferredembodiment, the flexible, lockable arm 37 is a series of interconnectinglinks 38 having a cable 39 running through the center of eachinterconnecting link 38 such that when tension is exerted on the cable39, the flexible, lockable arm 37 is fixed in a rigid position. FIG. 6also shows an embodiment of the invention wherein the contact members 1are comprised of a pair of substantially parallel elements 1 a, 1 bwhich are positioned to receive a simple snap fixture 40 which isaffixed to the surface of the heart. In this embodiment, the snapfixture 40 is positioned between the two parallel elements 1 a, 1 b ofthe contact member 1, in order to fix the position of the heart tissuerelative to the contact members 1. As in the above embodiment, thecontact members 1 are preferably oriented in a substantially parallelfashion with the target artery of the anastomosis passing therebetween.The snap fixtures 40 are affixed to the heart by a suture, wherein thesuture line 41 may then also be attached to the contact member 1 via anotch, which may form a one-way locking mechanism to secure the sutureline 41, or may be attached to a circular post disposed in the body ofthe contact member 1. The suture line 41 then may be tied through thenotch or to the post in the contact member 1 to more tightly secure theheart to the contact member 1. An additional advantage of thisembodiment is that the stabilizing means is actually affixed to thecardiac tissue via the suture line 41, such that when the heart ismoving laterally or downward the artery being stabilized remainsimmobile.

Referring to FIG. 7, a stabilizing means 60 is comprised of asubstantially planar and substantially rigid surface 62 having acentrally disposed opening 61 in which the target artery of theanastomosis is positioned longitudinally through the opening. At eitheror both ends of the centrally disposed opening 61, an occluder 63extends below the surface 62 and engages the target artery tosubstantially reduce or eliminate the flow of blood through the artery.The occluder is a rigid member having a smooth outer surface forcontacting and depressing the target artery without damaging the tissue.The planar surface 62 of the stabilizing means also has an aperture 64comprising an opening which traverses the entire planar surface 62 sothat the anastomosis can be passed through the aperture 64 when theanastomosis is completed. The planar surface 62 may also provide amounting surface for springed tissue retractors 65 comprising a coiledspring 66 attached to the planar surface at one end and having a hook orpin 67 at the opposite end to engage and spread the tissue proximate tothe anastomosis site to improve the exposure of the target artery. Theplanar surface 62 is attached to a post 69 which may be attached to astable support such as the rib retractor as shown in FIG. 9b. The planarsurface 62 may also have at least one port 70 for receiving a sutureline.

Referring to FIG. 8, the stabilizing means may have operably associatedtherewith an artery occluder 42, which is preferably attached to thecontact members 1 or to the connecting shaft 2. The artery occluder 42may comprise a semi-rigid member which has a blunt portion 43, which maybe positioned such that the blunt portion 43 engages the target artery55 and compresses the target artery 55 to a point causing occlusion ofthe target artery 55 passing between the contact members 1 such that theblood flow through the artery is substantially reduced or eliminated.Preferably, the occluder 42 has a shaft portion 44 which traverses theconnection shaft 2 such that the blunt portion 43 of the occluder 42 maymove from above the level of the target artery 55 to a point sufficientto occlude the blood flow.

Referring to FIG. 9A, the means for stabilizing the beating heart 4 ofthe invention is shown in use together with a rib retractor 50 andadditional apparatus 51, 52 which may be used during the beating heartCABG procedure. In use, the blades 53 of the retractor separate theribs, thereby providing an access space for the introduction of surgicalinstruments, including the stabilizing means 54 of the invention. Thestabilizing means 54 is thus brought into contact with the heart suchthat the contact members are proximate to the target artery 55. Once thestabilizing force has been exerted, sufficient to minimize the motion ofthe beating heart, the stabilizing means 54 is fixed in place,preferably by attachment to the rib retractor 50.

Referring to FIG. 9B, the stabilizing means 54 is an embodimentsubstantially as described above and shown in FIG. 1 which is comprisedof a pair of rectangular, substantially planar contact members 1 whichare placed proximate to a target artery 55. The shaft means 3 isconformable such that it may be conveniently attached to the ribretractor 50. As shown in FIG. 9B, the surgeon may readily adjust theorientation and positioning of the contact members 1 relative to theshaft means 3 while the stabilizing means 54 is in continuous contactwith the heart by manipulating the thumbscrew 8 at the proximal end ofthe instrument.

FIG. 9c shows a later stage of the procedure at a point where theanastomosis is being completed by suturing at target artery 55. Thestabilizing means 54 thus maintains a stabilizing force at theanastomosis site for the duration of the procedure.

Referring to FIG. 10, as noted above, attachment to a rib retractor is apreferred technique for fixing the position and orientation of thestabilizing means. The stabilizing means of the invention may thereforeadvantageously attached to a fixture attached to a rib retractor 50 ormay be configured to be directly incorporated into the body of a portionof the rib retractor 50.

A surgical rib retractor 50 is generally comprised of a body 54 havingblades 53 attached thereto, which engage the ribs and spread the ribswhen the retractor 50 is operated to move the blades 53 apart from oneanother. The space created by the retracted blades 53 provides access tothe heart. Thus, once the retractor 50 is locked into the open position,the stabilizing means may be applied to the heart and a stabilizingforce maintained at the site of the anastomosis by fixing the positionand orientation of the shaft means 3 relative to the rib retractor 50.Referring to FIG. 10, the shaft means 3 traverses the width of the body54 of the retractor 50 and is held in place by an upper plate 57 and alower plate 58 having circular openings 59 therein through which theshaft means 3 passes and which maintain the position of a sphere 56positioned between the upper plate 57 and lower plate 58. The size ofthe openings 59 is larger than the diameter of the shaft means 3 butsmaller than the largest diameter of the sphere 56. Thus, the shaftmeans 3 passes through the sphere 56 and may pivot about a pointapproximately at the center of the sphere 56.

Referring to FIGS. 11 and 12, because the available access and workingspace for the surgeon may be limited, certain embodiments of theinvention may be contained substantially within the chest cavity.Preferably, the stabilizing means is connected to the bottom of the ribretractor 50 on each side of the opening created by spreading the ribsusing the rib retractor 50.

Referring to FIG. 11, rib retractor 50 is shown in an open positionwhereby blades 53 engage and spread the ribs. A pair of stabilizing bars72 having a conventional ratchet means 73 attached at the end thereofare positioned beneath the retractor. The ratchet means 73 is comprisedof a plurality of teeth 74 on the stabilizing bars 72 and a ratchetingaperture 75 permitting one-way passage of the stabilizing bars 72 unlessreleased by a release mechanism. The stablizing bars 72 are curveddownward such that as the bars are advanced through the ratchet means73, the lowermost portion 76 of the stablizing bars 72 engages thebeating heart proximate to the anastomosis site.

Referring to FIG. 12, the orientation of the portion of the stabilizingmeans which engages the heart relative to the rib retractor 50 issimilar to the embodiment shown in FIG. 11. In this embodiment, acontact member 1 is attached on opposite ends to at least two malleablesupports 80 which are in turn attached to the rib retractor 50. Themalleable supports 80 are preferably made of stainless steel bands whichare woven in a mesh or have a repeating serpentine configuration toallow for substantial expansion within the chest cavity. Thisconfiguration yields a malleable support 80 with sufficient tensilestrength to maintain a stabilizing force at the anastomosis site whileallowing the surgeon to manipulate the malleable supports within thechest cavity to achieve the desired orientation relative to the beatingheart.

The particular examples set forth herein are instructional and shouldnot be interpreted as limitations on the applications to which those ofordinary skill are able to apply this invention. Modifications and otheruses are available to those skilled in the art which are encompassedwithin the spirit and scope of the following claims.

What is claimed is:
 1. A method to install a coronary artery bypass graft from a source artery to a target coronary artery while the heart is beating comprising the steps of: 1) providing an access space to the beating heart by a surgical procedure selected from the group consisting of a thoracotomy and a sternotomy, 2) introducing a stabilizing means through the access space, 3) contacting the surface of the beating heart proximate to the target artery at an anastomosis with a stabilizing means, 4) exerting a stabilizing force on the beating heart by positioning the stabilizing means, 5) restricting blood flow through the target artery while allowing the heart to continue to beat, 6) sewing an anastomosis to the target artery, 7) re-establishing blood flow through the target artery.
 2. A device for use in cardiovascular surgery on a beating heart, comprising: a flexible lockable arm having a distal end and a proximal end; a pair of contact members mounted to said distal end of said flexible lockable arm and adapted to contact a portion of the beating heart; and a cable extending substantially the length of said flexible lockable arm and adapted to lock said arm in a substantially rigid state as well as unlock said arm to assume a substantially flexible state.
 3. The device of claim 2, wherein said pair of contact members are positioned substantially in parallel to one another.
 4. The device of claim 2, wherein said flexible lockable arm assumes said substantially rigid state upon tensioning said cable and said flexible lockable arm assumes said substantially flexible state upon releasing tension from said cable.
 5. The device of claim 2, wherein said flexible lockable arm comprises a plurality of interconnecting links.
 6. The device of claim 5, wherein each said link comprises a ball portion and a receiving portion, such that said ball portion fits conformingly into an adjacent one of said receiving portions.
 7. The device of claim 5, wherein said cable runs through a center of each of said plurality of interconnecting links.
 8. The device of claim 2, wherein each of said pair of contact members comprises a pair of contact elements.
 9. The device of claim 8, wherein each said pair of contact elements are substantially in parallel alignment.
 10. The device of claim 8, further comprising a snap fixture received between each said pair of contact elements and adapted to be affixed to a portion of the beating heart.
 11. The device of claim 10, further comprising a suture associated with each said snap fixture and adapted to suture said snap fixture to the surface of the heart.
 12. The device of claim 11, wherein each said suture is further affixed to a respective one of said contact members.
 13. The device of claim 2, wherein said flexible lockable arm may be oriented in several directions when in said substantially flexible state.
 14. The device of claim 2, wherein said flexible lockable arm allows positioning in every direction to place and orient said contact member.
 15. A device for use in cardiovascular surgery on a beating heart, comprising: a plurality of interconnecting links forming a flexible arm having a distal end and a proximal end; a cable extending substantially the length of said flexible arm through said plurality of interconnecting links; and a pair of contact members mounted to said distal end of said flexible arm and adapted to contact a portion of the beating heart.
 16. The device of claim 15, wherein tensioning of said cable locks said flexible arm into a substantially rigid state, and release of tension from said cable allows said flexible arm to resume a substantially flexible state.
 17. The device of claim 15, wherein said flexible arm allows positioning in every direction to place and orient said contact members.
 18. A method of stabilizing a portion of a beating heart, said method comprising the steps of: contacting a surface of the beating heart with a contact member of a device comprising a flexible lockable arm having a distal end and a proximal end, a contact member mounted to said distal end of said flexible lockable arm, and a cable extending substantially the length of said flexible lockable arm and adapted to lock said arm in a substantially rigid state as well as unlock said arm to assume a substantially flexible state; contacting the surface of the beating heart with the contact member; and tensioning the cable to place said flexible lockable arm in said substantially rigid state.
 19. The method of claim 18, further comprising manipulating said flexible arm while in said substantially flexible state to achieve a desired orientation of the contact member for contacting the surface of the beating heart.
 20. The method of claim 18, further comprising fixing the position of the device by attaching the device to a fixed support.
 21. The method of claim 18, wherein said contacting a surface of the beating heart is performed with a pair of contact members.
 22. A method of stabilizing a portion of a beating heart, said method comprising the steps of: contacting a surface of the beating heart with at least one contact member of a stabilizing device having a stabilizing member capable of assuming a fixed state and an unfixed state; maintaining the at least one member in contact with the surface of the beating heart; and fixing the stabilizing member to assume the fixed state, relative to the beating heart to maintain the contact of the at least one contact member on the surface of the beating heart.
 23. The method of claim 22, wherein a retractor is used to form an access opening to the beating heart, and wherein said fixing comprises fixing the stabilizing device to the retractor.
 24. The method of claim 22, wherein the stabilizing device comprises a pair of contact members, the pair of contact members stabilizing surface portions of the beating heart on opposite sides of a target artery.
 25. A method of creating an anastomosis to a target coronary artery of a beating heart during performance of a coronary artery bypass surgical procedure, said method comprising the steps of: making an incision in the chest cavity of a patient; inserting a retractor into the incision and actuating the retractor to form an access opening for accessing the beating heart; introducing a stabilizing device through the access opening; engaging a surface of the beating heart proximate to the target coronary artery with at least one contact member of the stabilizing device; and fixing the stabilizing device to the retractor to maintain the position of the at least one contact member on the surface of the beating heart, for a duration of the surgical procedure sufficient to create the anastomosis. 